Code readers are ubiquitous in our daily lives, allowing humans to provide information to an electronic device or system without manually entering the information through a keyboard or a keypad. One type of code reader that is often used are barcode readers, which decodes visual information encoded in a barcode by shining a light source on the barcode and measuring the light reflected from the barcode. Another type of code reader that is often used are OR code readers, which processes a digital photograph of a QR code and decodes the visual information encoded in the QR code. Both barcode readers and QR code readers are costly and complex because they require generating a light source, a lens, a light sensor, and a heavy processor for processing and decoding the visual information.
An alternative to providing a code reader is to ask a human user to provide the information manually. However, such an alternative is prone to user errors (e.g., reading and/or entering a code incorrectly). Furthermore, the alternative is often inconvenient to users who do not wish to provide manual input, or who cannot easily provide manual input.
In one example, it is inconvenient and undesirable to request human users to manually enter a code to a glucose meter to identify/distinguish batches of glucose meter test strips. Typically, a glucose meter accepts a consumable element containing chemicals that react with glucose in the drop of blood is used for each measurement. For some models this element is a plastic test strip with a small spot impregnated with glucose oxidase and other components. Each strip is used once and then discarded. Instead of strips, some models use discs, drums, or cartridges that contain the consumable material for multiple tests. Since test strips may vary from batch to batch, some models require the user to manually enter in a code found on the vial of test strips or on a chip that comes with the test strip. By entering the coding or chip into the glucose meter, the meter will be calibrated to that batch of test strips. However, if this process is carried out incorrectly, the meter reading can be up to 4 mmol/L (72 mg/dL) inaccurate. The implications of an incorrectly coded meter can be serious for patients actively managing their diabetes. This may place patients at increased risk of hypoglycemia.